1. Field of the Invention
This invention relates to catheters and materials for catheters, particularly everting thru-lumen balloon catheters with flexible balloons. The invention is particularly useful in catheters for dilatation, the inflation and/or repeated inflation of a balloon within a plaque occlusion or stenosis to reform the plaque deposit against the vessel wall and open the vessel.
2. Description of the Prior Art
Balloon catheters and everting balloon catheters are known in the art. For example, as disclosed in U.S. Pat. Nos. 4,437,857, 4,604,094 and 4,530,698, method and apparatus for everting a balloon using a balloon material substantially more flexible than that of the catheter body is known. Flexible but non-elastomeric balloon materials such as polyethylene are used for the balloons as disclosed in U.S. Pat. Nos. 4,493,711 and 4,606,347.
The use of an internal, slidable, tubular sheath to enhance the eversion process is shown in EPO Patent Application 86630101.1 and a seal for the thru-lumen is shown in U.S. Pat. No. 4,606,347. Also, U.S. Pat. Nos. 4,526,175 and 4,689,041 show different balloon structures.
Methods and apparatus for everting a tube are shown in U.S. Pat. No. 3,506,011. As shown in U.S. Pat. No. 4,271,839, the use of a balloon attached to slidable thru-lumen tubing or reinversion member at one end of the balloon and to the catheter body at the other end Express Mail Label No. RB310995113 of the balloon so that the balloon is everted by sliding the thru-lumen tubing distally is known for dilatation.
A problem, though, with standard designs for such a thru-lumen everting balloon is that the inverted balloon tends to result in a large, if not flared, catheter tip, difficult to slide through the tortuous pathways of the vascular system. Finally, prior art dilatation balloons are normally attached to the outer catheter body by adhesives, which frequently result in leakage and bond deterioration during inflation.